Why does the Torah say both, "va'Yeshalechu... va'Yavi'u" (they sent it... they brought it)?
Ramban #1, Da'as Zekenim #1: They sent it from Dosan to their father with whoever was going to Chevron.
Ramban #2: They sent it to Chevron to one of their homes, and when they returned to Chevron, they brought it to him personally. 1
Rashbam: They sent the robe via unspecified messengers, who would make out to Yaakov that they (the messengers) had found it, to deflect Yaakov's suspicions from them.
Targum Yonasan: They sent it via the sons of Bilhah and Zilpah, Yosef's friends, in order to deflect Yaakov's suspicions from them.
Ramban #3, Da'as Zekenim #2, Rosh and Seforno, Ha'amek Davar: The word "va'Yeshalechu" means that they made incisions in it, 2 to resemble the teeth-marks of a wild beast.
As implied by the continuation of the Pasuk.
From the word 'Shelach' - a sword, as in Iyov 36:12. Gur Aryeh - This cannot be correct; for if they first dipped the garment in blood and then sliced it, the dry edges of the tear would have shown the forgery. Rather, it means "they sent it [with a messenger]."
Why did they send the bloody cloak with a messenger, rather than bringing it themselves?
Rashbam, Targum Yonasan: In order to deflect Yaakov's suspicions from them.
Gur Aryeh: One should avoid being the one to relate bad news; see Pesachim 3b.
